Light emitting diodes (LEDs) are used in a plurality of application fields. White LEDs are, for example, used in general lighting applications and for TV or monitor backlighting applications. For all these applications, light emitting diodes are the main part of the overall bill of material. The intensity of the light emission of an LED is dependent on the level of current driven through the LED. The larger the operating LED current, the larger is the light intensity emitted by the LED. Therefore, high LED current values are desirable to maximize light output with a restricted number of LEDs.
The main limitation of increasing the current driven through an LED is the temperature rise inside of the LED because of power dissipation. Too high temperatures can cause degradation of the LED with reduced lifetime and early life failures. Therefore, monitoring the temperature of an LED during its operation is an important matter.
It is desirable to provide an electronic circuit to monitor a temperature of a light emitting diode to ensure a reliable operation of the light emitting diode. A further concern is to provide a method to monitor a temperature of a light emitting diode to ensure a reliable operation of the light emitting diode.